The present invention relates to a multicolor electrophotography apparatus for making a multicolor image by superimposing a plurality of colored images on the same copy sheet.
The manner of obtaining an electrostatic image upon a charged surface is well known in the art of electrophotography and may be carried out in any one of several ways known as the "Electrofax method". A typical process may include for example, producing an over-all electrostatic charge on the surface of a photoconductive sheet such as selenium, or zinc oxide dispersed in an insulating binder. A light image is focused on the charged surface, discharging the portions irradiated by the light rays, while leaving the remainder of the surface in a charged condition, to thus form a latent image. The latent image is rendered visible by applying a developer toner and then held to the charged areas of the surface. The toner image thus formed may be fixed directly to the photoconductive sheet.
Reproduction of images in a plurality of colors, in general, consists of forming of a uniform electrostatic charge over the surface of the photosensitive sheet by virtue of corona behavior, exposing the photosensitive sheet to an original through light filters which enable one color latent image to be recorded, and then rendering the color latent image visible by development with colored toner. The procedure is repeated for each color by superimposing the color images on the same photoconductive sheet.
Nevertheless, registration of the separate images is the greatest problem associated with the production of plural color images.
An object of the present invention is to provide an improved multicolor electrophotography apparatus which insures that one color image will be superimposed in exact registration with another upon a copy sheet.
Another object of the present invention is to provide an improved multicolor electrophotography apparatus which simplifies the construction for carrying a photosensitive copy sheet over stations, for example, the series of a charge formation station, the exposure station and the development station.
A further object is to provide an improved multicolor electrophotography apparatus which insures that a photosensitive copy sheet will be held at an exact even plane during exposure.